Process for three-dimensional modeling and design of off-highway dump bodies

ABSTRACT

A process for designing dump bodies which more accurately takes into account field loading/haulage conditions is provided. The process includes gathering data from actual field environments including material density, front, rear and side angles of material repose and corner void information. From this data, a three dimensional model of the load is generated. This three dimensional load model is then used to design the truck body in an iterative process until the volume of the truck body and the distribution of weight of the three dimensional load model on the truck chassis is substantially the same as the desired volume and the distribution of weight on the truck chassis.

FIELD OF THE INVENTION

The present invention relates generally to heavy-duty off-highwaytrucks, and more particularly to a process for designing an off-highwaytruck dump body.

BACKGROUND OF THE INVENTION

In mining and construction environments, heavy-duty off-highway trucksare used to haul a variety of materials such as, for example, coal,rock, ore, and overburden materials. Such heavy-duty off-highway trucksgenerally comprise a truck chassis or frame which supports a dump bodyfor receiving and carrying a load. In order to ensure that the dump bodyis properly balanced, the dump body should be designed based on ananticipated load distribution of the material carried on the truckchassis or frame. More specifically, the truck chassis anticipates aparticular optimal location on the chassis where the center of gravityof the load carried in the dump body should be positioned.

Trucks with dump bodies which are often sold by the original equipmentmanufacturers have dump bodies designed around an assumed loadconfiguration or load profile. In designing these dump bodies, however,the load profile which is used to size the body is based on atheoretical material angle of repose or load heap of the materialirrespective of material cohesiveness, individual material heapingcharacteristics or material gradation. For example, in designing a dumpbody for overburden, a theoretical material heap of 2:1 (or a differentS.A.E. 2:1 heap) is-often assumed.

Historically, off-highway truck manufacturers have been unable to reacha consensus with regards to the theoretical load heaps orconfigurations, let alone any consensus on the individual hauledmaterial characteristics that should be used to design the dump bodies.As evidenced by their commercially available literature, someoff-highway truck manufacturers use theoretical material heap profilesbased on standards promulgated by the Society of Automotive Engineers(S.A.E. J 1363 Jan. 1985) while others use their own heap profiles.Moreover, many off-highway truck manufacturers have over time alternatedbetween using various different theoretical load heap profiles orconfigurations to design their dump bodies.

Off-highway truck manufacturers use these theoretical load heap profilesso that they are able to mass produce their dump bodies. However, thetheoretical load heap, and the resulting theoretical load profiles,which the truck manufacturers use to design their dump bodies ignore anumber of factors. For example, theoretical load profiles do not takeinto account the particular material characteristics of the materialbeing loaded and hauled. In addition, theoretical load profiles do nottake into account the corner voids which occur when a load is placed inthe dump body. In particular, since the material is loaded from overheadinto the dump body, the material tends to try to form a generallyconical shape in the dump body. Because the load conforms to a generallyconical shape, voids are created in the corners of the dump body whereno material is present. The theoretical load profiles as used by truckmanufacturers ignore these corner voids.

Additionally, field loading/haulage conditions impact the actual anglesof repose that the loaded material forms in the dump body. In theloading process, material on its own flows to a natural angle of repose,however, in the loading process as the loading equipment pushes/pullsand rests on the material being loaded an imposed material angle ofrepose results. For instance, the method by which the material isactually loaded into the dump body, e.g. using a front-end loader or ashovel, can impact the ultimate actual profile of the load in the body.Other material characteristics such as the cohesiveness, gradation, sizeand consistency of the material (e.g., ore, overburden, clay, etc.) alsoimpacts the actual load profile. Accordingly, because of differences inthe materials and field loading and haulage conditions, the actual loadprofile or configuration of given materials in the dump body atdifferent sites can vary extensively.

As a result, the mass-produced dump bodies supplied by off-highway truckmanufacturers which are based on a theoretical material load profile areoften improperly a matched for a particular material haulageapplication. For example, the dump body may be inadvertently designedsuch that the dump body size and resultant load is eitherundersized/underloaded or oversized/overloaded and that thecorresponding center of gravity of the actual load is significantlyoffset from where it should be placed, based on the design of the truckchassis. This causes incorrect truck loading and improper truckutilization with uneven loading of the truck chassis leading to unevenor offset frame loading, which can potentially result in truck chassisproblems including uneven tire wear which often requires prematurereplacement of the tires; and potentially poor vehicle operatingstability. As will be appreciated, since the trucks themselves and thetires used on these types of off-highway trucks are extremely costly,potential truck chassis repair and premature replacement of tiressignificantly increases the operating expenses associated with materialhaulage.

Likewise, depending on how the actual material and material heap variesfrom a theoretical material load profile, the dump body can be eithertoo large or too small resulting in the truck chassis carrying loadswhich are both improperly placed on the truck frame and significantlyheavier or lighter than intended. An improperly designed body which istoo small to carry the intended load can lead to spillage of the loadover the sides and off the rear end of the body resulting in significantunder utilization of the truck. If side/rear spillage occurs duringtransport, it can result in tire damage and tire ruptures particularlyon the following trucks. While too large of a body for the intended loadcan result in extreme truck overloads or if the load is limited to thecorrect load amount in the dump body, the load may often be improperlyplaced in the dump body leading to poor truck stability and individualtruck chassis component overloads.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, in view of the foregoing, a general object of the inventionis to provide a dump body which is designed for specific field operatingenvironments.

A related object is to provide a method for designing off-highway dumpbodies which more accurately takes into account actual field conditions.

A more specific object is to provide a process for three-dimensionalmodeling of required dump body loads and the related design of dumpbodies based on actual field conditions at particular sites.

These and other features and advantages of the invention will be morereadily apparent upon reading the following description of a preferredexemplary embodiment of the invention and upon reference to theaccompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-7 are side views and a rear view (FIG. 6) of a heavy-duty,off-highway truck illustrating a portion of an exemplary sequence ofprocess steps for designing a dump body for the truck in accordance withthe present invention.

FIG. 8A is a side view of a dump body (outlined in triple solid lines)and a material heap (outline in broken lines) illustrating a processstep in the sequence of steps for developing a three-dimensional heapedmaterial load profile based on data collected from a specific haulageenvironment for use in the dump body design process of the presentinvention.

FIG. 8B is a rear view of the dump body (outlined in triple solid lines)and the material heap (outlined in broken lines) of FIG. 8A illustratinga process step in the sequence of steps for developing thethree-dimensional heaped load profile.

FIG. 9 is top view of the dump body and material heap of FIGS. 8A and 8Billustrating in part how the corners of the heaped load are modeledbased on an incremental blending of the side angles of material reposeto the front and rear angles of material repose to develop thethree-dimensional modeled material heap profile.

FIGS. 10 a and 10 b are top views of the dump body and material heap ofFIGS. 8A and 8B illustrating in part how the corners of the heaped loadare modeled based on an incremental blending of the side angles ofmaterial repose to the front and rear angles of material repose todevelop the three-dimensional modeled material heap profile.

FIGS. 10 c and 11 are perspective views of the dump body and materialheap of FIGS. 8A and 8B illustrating in part how the corners of theheaped load are modeled based on an incremental blending of the sideangles of material repose to the front and rear angles of materialrepose to develop the three-dimensional modeled material heap profile.

FIG. 12 is a side view of the dump body and material heap of FIGS. 8Aand 8B illustrating in part how the corners of the heaped load aremodeled based on an incremental blending of the side angles of materialrepose to the front and rear angles of material repose to develop thethree-dimensional modeled material heap profile.

FIG. 13 is a perspective view of the dump body and material heap of FIG.8A and 8B illustrating how the corners of the heaped load are modeledbased on an incremental blending of the side angles of material reposeto the front and rear angles of material repose to develop thethree-dimensional modeled material heap profile.

FIG. 14 is a perspective view of the final three-dimensional modeledmaterial heap profile for use in the dump body design process of thepresent invention.

FIG. 15 is a perspective view of the three-dimensional modeled materialheap profile of FIG. 14 in the dump body of FIGS. 8A and 8B.

FIG. 16 is a side view of the off-highway truck of FIGS. 1-7 having thedump body and material heap profile of FIG. 15 illustrating a furtherstep in the dump body design process of the present invention.

FIG. 17 is a side view illustrating the final design of the dump body.

FIGS. 18 a-b are a flow diagram of an exemplary embodiment of the designprocess of the present invention.

FIG. 19 is perspective drawing illustrating the differences between thethree-dimensional heaped load profile of FIG. 15 and a load profileproduced using a S.A.E. J 1363 (Jan. 1985) 2:1 heap rating standard anda load profile produced using a 2:1 straight heap rating.

FIG. 20 is a comparison diagram illustrating the differences between thethree-dimensional modeled material heap load profile of FIG. 15 ascarried in a dump body and a straight 2:1 heap load profile and a S.A.E.2:1 heap load profile as carried in the same dump body.

FIG. 21 is a side view of an off-highway truck carrying a load in anexemplary field operating environment.

FIG. 22 is an end view of an off-highway truck carrying a load in anexemplary field operating environment.

While the invention will be described and disclosed in connection withcertain preferred embodiments and procedures, it is not intended tolimit the invention to those specific embodiments. Rather it is intendedto cover all such alternative embodiments and modifications as fallwithin the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now more particularly to the drawings there is shown in FIGS.1-17 an illustrative sequence of process steps for designing a dump body10 for an heavy-duty off-highway truck 12 in accordance with theteachings of the present invention. The truck 12 includes a chassis 14to which the dump body 10 is attached for pivotal movement about an axisbetween a lowered position for receiving and transporting a load ofmaterial and a raised position for dumping a load of material. As shownin FIG. 17, the dump body 10 is generally constructed of steel panelswhich define the shape of the dump body and beams which form thestructural framework for the dump body. The dump body comprises, in thiscase, sidewalls 16, a front wall or front slope 18, a floor 20 and acanopy 22 integrally connected to the top end of the front slope 18 andextending over the cab 24 of the truck 12. The truck chassis 14 issupported by a plurality of tires 26.

In the illustrated embodiment, the truck 12 is generally symmetricalabout its longitudinal axis. Accordingly, as will be appreciated, manyof the elements identified in the side views of FIGS. 1-7 havecomplementary elements arranged on the opposite side of the truck 12. Aswill be appreciated, reference to plural elements where only one isshown indicate that a complementary element is disposed on the side ofthe truck 12 not shown (e.g., sidewalls 16).

In accordance with an important aspect of the present invention, thedump body 10 is designed so that the volumetric capacity of the dumpbody matches the truck hauling capacity and that loads in the dump bodyhave a center of gravity that best matches the intended load center ofgravity/corresponding load distribution contemplated by the design ofthe truck chassis 14. More specifically, the dump body 10 is shaped anddimensioned to accommodate the correct volumetric load as well as tomaintain a load distribution that results in the center of gravity ofthe load being proximate a predetermined location, in this case, thepreferred position for the load center of gravity based on the truckmanufacturer's designed chassis loading/weight distribution. Unlikeprevious dump body design methods, the dump body design of the presentinvention is not based on an assumed theoretical or universal loadprofile/load material heap. Instead, the present invention utilizes aload profile that is based on a detailed analysis of the actual materialcharacteristics and loading conditions present in specific field haulageenvironments thereby taking into account factors such as thecohesiveness of the material to be hauled and the size, shape andgradation of the pieces of material.

For example, U.S. Pat. No. 5,887,914 issued to LeRoy G. Hagenbuch onMar. 30, 1999 discloses a dump body design process which can be used toproduce a dump body that is capable of hauling both overburden and coal.This design process assumes a theoretical 2:1 heap for overburden and atheoretical 3:1 heap for coal. It has been found that these theoreticalload profile assumptions do not always provide an accurate body designof the actual haulage operating conditions which are encountered atspecific job sites. Such theoretical body load profiles, are usedwithout any consideration of the actual material, loading and haulingconditions that exist at actual locations of use. Thus, in many casesthe dump body can be improperly sized and designed or matched to thematerial to be hauled and accordingly to the truck chassis.

In order to more accurately take into account actual field conditions,the first step in the design process of the present invention is tocollect field data relating to the material characteristics and loadconfigurations currently being hauled by trucks at the site at which thedump body 10 will be used. In particular, data should be collected withregard to the actual angles of material repose, the size and shape ofany plateau formed at the top of the load and loading voids that areformed by the material when it is loaded and carried in existing dumpbodies. The angles of material repose are dependent upon a number offactors including the cohesiveness of the material being hauled and thesize, shape and gradation of the material pieces. With respect toanalyzing the angles of repose, load plateau and loading voids of theloaded material, one method by which this can be accomplished is tophotograph (or videotape) from various different angles the loads 72presently being hauled by one or more existing off-highway trucks 74 ata site (see, e.g., FIGS. 21 and 22). More specifically, photographsshould be taken of loads 72 carried by several different existing trucks74 with photographs being taken from the front, back, corners (front andrear) and sides of those trucks. In order to help identify any shiftingof the load that may effect load profiles and which may occur duringtransport, photographs can be taken of the loaded trucks as they areleaving the loading area as well as when they are traveling on the haulroads.

Furthermore, since the method by which material is loaded into the truck12 can also impact the loaded material profile, it can also be useful tocollect data, via photographs or otherwise, regarding truck loadingtechniques and the equipment used to load the dump bodies. For example,front-end loaders generally have a wide bucket relative to the dump bodylength and typically load material into the dump body from the side ofthe truck. Accordingly, when front end-loaders will be used to load thedump body, the length of the dump body can be an important factor.Likewise, cable and hydraulic shovels tend to have narrower buckets andare also used to load material into the body typically from the side ofthe truck. Since cable shovels typically have a door which swings towardthe shovel when dumping (i.e. towards the side of the body), the widthof the body may be an important factor when shovels will be used to loadthe dump body. Additionally, information should be collected giving anaccurate material density. The types of information which can berelevant to determining the density of the load material include visualexaminations of the load material, the taking of weight samples of knownvolumes of the load material and consultations with the end user of theproposed dump body.

In some circumstances, such as in the case of a new mine, it may not bepossible or desirable to collect material and loading data from the siteat which the dump body 10 will be used. In these situations, data from asimilar field haulage environment should be used. As will be appreciatedby those skilled in the art, a similar field haulage environment wouldhave conditions that parallel as closely as possible the conditionswhich are anticipated at the new site. This could include, for example,a nearby site or mine in which the same or similar material is hauled, asite hauling similar materials and using similar hauling equipmentand/or a site using similar loading equipment. Once the new mine or siteis operational, the design of future dump bodies for that site can berefined as needed and as information is developed about the material andloading conditions at the site. Of course, the material and loadingconditions at sites will, in most cases, evolve over time which couldnecessitate further analysis of these parameters prior to the design ofnew additional dump bodies for that site.

Once the appropriate load heap pictorial information has been collected,the information is then analyzed to determine what are the actual anglesof material repose of the loaded material and the dimensions of the topplateau of the material heap. In one presently preferred embodiment,this is accomplished by blowing up at least select representativephotographs of off-highway trucks with loaded material. From these blownup photographs, the size of the plateau of the heap, the angles ofmaterial repose and the corner voids of the loaded materials are thenmeasured. In most cases, the angles of material repose that run to thefront, rear and sides of the dump body will all be somewhat differentnamely due to the natural and imposed angles of repose occurring as aresult of the loading process. Accordingly, using the photographs,values should be determined for each of these angles repose. The variousvalues for the front, rear and side angles of repose which are measuredfrom the photographs are compiled and averaged respectively in order toproduce a composite front angle of repose, a composite rear angle ofrepose and a composite side angle of repose which can then be used tocreate a three-dimensional load profile as described in greater detailbelow. Of course, as will be appreciated by those skilled in the art,other methods may be used to collect and analyze the data on actual dumpbody field haulage conditions including, for example, actual hands-onmeasurements of the relevant angles of repose and corner voids.

Using the values of the empty and loaded weights of the truck 12provided by the off-highway truck manufacturer, the ideal position alongthe chassis 14 for the load center of gravity is then determined. Asillustrated in FIG. 1, the correct load center of gravity on the chassis14 (represented by arrow 28 in the drawings) is located usingconventional moment diagrams.

To begin designing the body 10, as shown in FIG. 2, a line 30 isestablished-to represent the plane of the dump body floor. Generally,the angle of the floor line 30 is established to provide an incline withrespect to the horizontal plane as illustrated in FIG. 3 and isestablished at a set minimum distance above the chassis 14 at the frontof the body and a set minimum distance above the chassis and/or tires atthe rear of the body. A proposed line 32 for the front slope of the dumpbody is also established, as shown in FIG. 3, at a set minimum distanceback from the chassis deck/engine compartment at the bottom end of thefront slope and at a set minimum distance back from the chassis cab 24at the upper portion of the front slope. To minimize the vertical heightof the center of gravity of the load, it is preferable to set theinitial front slope line 32 as far forward and the initial floor line 30as low as possible while still maintaining the appropriate clearancesfor the truck cab 24 and chassis 14. As shown in FIG. 4, the initialproposed inside body width of the body 10 is then set based on 90-115%of the overall rear axle tire width or as set by the truck chassismanufacturer.

As shown in FIGS. 5 and 6, using the angles of material repose (i.e.front, rear and sides) data obtained from the analysis of the actualfield haulage conditions, an approximate heap profile 33 of the materialto be hauled is then generated utilizing the individual average valuesfor the front, rear and sides angles of material repose 34, 36, 40(e.g., 24°, 30° and 32° respectively in the illustrated embodiment)taken from the field data. Additionally, as shown in FIG. 5, an initialdump body side height (referenced as line 37) is established at thepoint where the front angle of material repose 34 contacts the frontslope line 32. The placement of the center of gravity of the approximateheap profile 33 along the truck chassis 14 is then determined andcompared with the optimal location along the chassis for the load centerof gravity (arrow 28).

The angle of the floor line 30, the lengths of the front slope line andfloor line and the line defining the height of the sidewalls areadjusted as indicated by the arrows in FIG. 7 so that through aniterative process, the center of gravity of the load can be located asclose as possible to the correct truck chassis 14 load center of gravitywhile maintaining the desired body volume. In adjusting the variousparameters, it is preferable to keep the center of gravity of the loadas low as possible in order to provide the best truck chassis stability.Accordingly, in the iterative process used to locate the center ofgravity of the load in the desired position, it is generally preferableto focus on adjusting the height of the sidewalls and the length of thefloor, versus rotating the rear of the floor. For example, eitherlowering the sidewalls and lengthening the floor to move the center ofgravity rearward relative to the chassis 14 or raising the sidewalls andshortening the floor to move the center of gravity forward relative tothe chassis 14. Using an iterative process, the width of the body 10 mayalso be adjusted with the slopes and lengths (within given parameters)of the floor and front slope in order to minimize the overall loadheight profile. While overall loading height of the dump body influencesthe size of the loading equipment that is required, lower overall dumpbody loading heights improve truck stability and lessen the need forlarger loading equipment. Lower overall dump body loading heights alsonecessarily allow the load material to be dropped into the dump bodyfrom a lower point, thereby minimizing the impact force of the loadmaterial on the dump body. Obviously, the wider the body 10, the lowerthe center of gravity. As a practical limit, however, the body 10generally should not be significantly wider than the overall width ofthe rear axle measured from the outer edges of the rear tires or aspreset by the truck chassis manufacturer.

Next, based upon this approximate load profile 33 (e.g., shown in FIG.6) and the data on the actual field haulage conditions, athree-dimensional model 38 (e.g. shown in FIGS. 8-15) of the load heapis developed which incorporates corner voids and the actual side anglesof material repose 40 (e.g., 32°), front and rear angles of materialrepose 34, 36 (e.g. 24° and 30°) and a top of heaped load plateau 48 asmeasured from the actual field collected data. The process/steps used todevelop the three-dimensional modeled heaped material load profile 38are generally shown in FIGS. 8-15 with the outline of the truck body 10shown in triple solid lines and the outline of the three-dimensionalmodel 38 shown in broken lines. To account for corner voids (corners ofthe body where no hauled material is located) in the three-dimensionalmodeled load profile 38, the transition areas between the sides and thefront and the rear of the load are modeled based on a gradualincremental blending of the side angle of material repose 40 to thefront and rear angles of repose 34, 36 (which angles of repose may ormay not be different. After the corner voids are so modeled, the modeledvoids are then compared to the information collected in the field andthe corner voids may then be adjusted so as to as closely as possiblematch the modeled corner voids with the actual field corner voids. Aswill be appreciated, the steps described in FIGS. 5-7 are used only toexpedite the design process and are not necessary to the presentinvention. In particular, one can move directly to using thethree-dimensional model 38 of the load heap (with the corner voids) andeliminate the steps shown in FIGS. 5-7.

To this end, in one preferred embodiment, the transition areas betweenthe front 42 and the sides 44, and the rear 46 and the sides 44 of thethree-dimensional load model 38 are divided into a number of equalsegments as shown in FIG. 9. In the illustrated embodiment, the creationof the corner voids (e.g., FIG. 15) through the transitional blending ofthe angles of repose is only shown with respect to one of the frontcorners and one of the rear corners of the load. Of course, it will beappreciated that the same methodology described herein can be used tomodel the voids in the other corners of the load. In the illustratedembodiment, the boundaries of the transition areas between the sides 44and the front 42 and rear 46 portions of the three-dimensional loadmodel 38 form 90° angles defined by the flat top or plateau 48 (FIG. 8and 9), as defined by actual field operating data, of the load model 38,with each of the transition areas being divided into nine equal 100segments. Planes 50 (FIG. 9) are established in each of these segmentswhich extend at a respective angle of repose that allows, if required,an incremental change in the angle of repose through the corners fromthe sides 44 to the front 42 and rear 46 of the three-dimensional loadmodel 38. In particular, the difference between the side and rear anglesof repose, in this case 2°, and the side and front angles of repose, inthis case 8° is divided into nine equal incremental segments as shown inFIG. 9.

Each of these planes 50 is then extended using standard geometricprinciples until it intersects a portion of the dump body 10 such as thefloor, side walls, front slope or canopy as shown in FIGS. 10 a-c and11. Specifically, as shown in FIGS. 10 a-c, end points are establishedfor each of these planes by using the values of the angles of materialrepose for each of the segments and the horizontal distance for eachrespective segment from the appropriate corner of the load plateau 48 tothe perimeter of the dump body 10 to calculate the horizontal andvertical positions for the end points of the planes. Each plane 50 isthen extended to its respective end points (FIG. 11). Next, any portionof the planes 50 which extends beyond the boundaries of the dump body 10(referenced as 62, 64 and 66 in FIGS. 12-13) is then “cut-off” at thepoint at which it intersects the dump body to define the corner edges ofthe three-dimensional load model 38 as shown in FIGS. 12 and 13. Thecompleted three-dimensional load heap profile 38 is shown in FIG. 14 andarranged in the dump body 10 in FIG. 15.

Once the three-dimensional modeling of the material heap is completed,including the modeling of the corner voids along with a subsequentcomparison with the field gathered information, the center of gravity ofthe resulting three-dimensional load model 38 is then determined. Thiscenter of gravity is then compared to the center of gravity location(arrow 28) contemplated by the chassis design as shown in FIG. 16. Ifthe center of gravity of the three-dimensional load model 38 is in closeproximity to the center of gravity location contemplated by the chassisdesign then the design of the dump-body 10 is complete. It is generallydesirable to have the load center of gravity as close as is practical tothe desired chassis location. While the distance will vary dependingupon the relative length of the wheelbase of the truck, in one preferredembodiment the center of gravity will be considered sufficiently closeto the desired location if it is within less than one inch (plus orminus) from the desired location. Due to the inherent designcharacteristics of off-highway trucks (in an empty condition aninordinate amount of the net weight of the truck is carried on the frontaxle), in most circumstances, the center of gravity of thethree-dimensional load profile should not be allowed to be positionedforward of the center of gravity location contemplated by the chassisdesign.

In the event that the center of gravity of the three-dimensional loadmodel 38 is not close enough to the desired location, in an iterativeprocess a new three-dimensional profile of the heaped load is generatedbased on the data collected from the field loading/haulage environment.Through adjustment of the parameters of the dump body (e.g., the dumpbody floor angle, floor length and side height), the center of gravityof this new three-dimensional heaped load profile is moved through theiterative process until it is in close proximity to the desiredlocation. These steps being repeated in an iterative fashion asnecessary until the center of gravity of the three-dimensional loadmodel is adjusted to-be-approximately coincident with the anticipatedcenter of gravity contemplated by the design of the truck chassis 14.

The final design of the dump body 10 is shown in FIG. 17. In accordancewith the present invention, the body 10 is custom modeled/designed basedon specific field material, loading and hauling conditions and thus whenthe body is used in the field it will carry the desired volumetrichauling capacity and the center of gravity of the load will be in closerproximity to the desired center of gravity location than bodies designedusing theoretical heap load profiles (see, e.g., FIG. 20).

FIGS. 18 a-b are a flow diagram which illustrates the individual stepsin the design process of the present invention which are describedherein and shown in the drawings of FIGS. 1-17. For ease of reference,the steps in the flow diagram of FIGS. 18 a-b are numbered to correspondwith the numbering of the steps in FIGS. 1-17. As will be appreciated bythose skilled in the art, steps 6 and 7 shown in FIGS. 18 a-b can beconsidered optional in the design process.

As will be appreciated, the use of actual angles of repose gathered fromdata taken from the actual field haulage conditions in which the dumpbody 10 will be employed can have a significant impact on the model ofthe load and thus ultimately on the design of the dump body. Forexample, as shown in FIG. 19, in the illustrated example of a loadhaving actual 32° side, 24° front and 30° rear angles of repose, thethree-dimensional load modeling process of the present invention resultsin a significant amount of material being removed from the front andrear and through part of the corners of the three dimensional load model38 as compared to a standard 2:1 heap model 54 and a S.A.E. 2:1 heapmodel 52 as defined by S.A.E. Standard No. J 1263 (Jan. 1985) (with theprofiled three-dimensional model created using the present inventionshown in broken lines and the S.A.E. 2:1 heaped model and standard 2:1heaped model shown in solid lines). In this case, the three-dimensionalload modeling process of the present invention also results in asignificant amount of load material being added to the sides in thethree-dimensional load model 38 as compared to the S.A.E. 2:1 heap andthe standard 2:1 heap.

An example of how these differences in the load model can impact thelocation of the center of gravity of the load as it is carried in a dumpbody and the rated capacity or yardage of the dump body is shown in FIG.20 (which is a side view of the load models shown in FIG. 19). Moreparticularly, in FIG. 20, the location of the center of gravity andcapacity of the three dimensional load model 38 as carried in a dumpbody is compared to the center of gravity and rated capacity of loadmodels using the S.A.E. 2:1 heap standard model 52 or the 2:1 heap model54 in the same dump body. As can be seen, the use of the S.A.E. 2:1standard heap model 52 and the 2:1 heap model 54 results in the centerof gravity being offset from the ideal location and in an overstatementof the truck body capacity. Of course, FIGS. 19 and 20 provide just oneillustrative example of the differences between the three dimensionalmodeled heaped load profiles which result from using the process of thepresent invention as compared to heaped load models created usingtheoretical load profiles. Since the load modeling process of thepresent invention is dependent upon angle of repose data collected fromthe actual field haulage environment, the differences which result fromusing the load modeling process of the present invention as compared tothe theoretical load profiling will vary on a case-by-case basis.

In view of the foregoing, it will be appreciated that, unlike thetheoretical load profiling currently being done, the body and designprocess of the present invention takes into account the field material,loading and hauling conditions in which the dump body will be used andprovides a method by which this information can be used in a meaningfulmanner in designing the dump body. Thus, a much more accurately designeddump body is produced resulting in improved body capacity andcorresponding load retention, and proper placement of the load on thetruck chassis and tires.

All of the references cited herein, including patents, patentapplications, and publications, are hereby incorporated in theirentireties by reference.

While this invention has been described with an emphasis upon preferredembodiments, it will be obvious to those of ordinary skill in the artthat variations of the preferred embodiments may be used and that it isintended that the invention may be practiced otherwise than asspecifically described herein. Accordingly, this invention includes allmodifications encompassed within the spirit and scope of the inventionas defined by the following claims.

1. A process for making a body of a vehicle for hauling material havinga front wall, a pair of sidewalls and a rear edge, the processcomprising: (a) determining heaping characteristics of material to behauled at the vehicle's anticipated point of use, including at leastangles of material repose in three dimensions, wherein the angles ofmaterial repose include front, rear and side angles; (b) developing athree dimensional model of a load to be carried in the body on a chassisusing the angles of material repose; (c) adjusting a set of designparameters of the body until a center of gravity of the model is locatedproximate a desired location for a load center of gravity on the chassisand a volume of the three dimensional model is substantially similar toa desired volumetric capacity; and (d) producing the body in accordancewith the adjusted set of design parameters.
 2. The process according toclaim 1 wherein the set of design parameters of the body includes aposition of the body floor and a position of the body sidewalls.
 3. Theprocess according to claim 2 wherein the position of the body floorincludes a length of the floor.
 4. The process according to claim 2wherein the position of the body sidewalls includes a height of thesidewalls.
 5. The process according to claim 4 wherein the position ofthe body sidewalls further includes a distance between the respectivesidewalls.
 6. The process according to claim 4 further including the,step of adjusting a length of the body floor and the height of the bodysidewalls to provide a lowest practical vertical location for the centerof gravity of the three dimensional volumetric model of the hauledmaterial.
 7. The process according to claim 2 wherein the set of designparameters of the body further includes a position of the body frontwall.
 8. The process according to claim 1 wherein the heapingcharacteristics of material to be hauled at the anticipated point of usefurther includes a representation of an actual load.
 9. The processaccording to claim 8 wherein the heaping characteristics of material tobe hauled at the anticipated point of use includes angles of materialrepose and representations of corner voids present in the corners ofload-carrying vehicle bodies.
 10. The process according to claim 8wherein developing the three dimensional model of a load to be carriedin the body includes developing the three dimensional load model toaccount for corner voids in the vehicle body.
 11. The process accordingto claim 10 wherein the three dimensional model is developed through agradual incremental blending of the respective side angles of materialrepose to the front angle of material repose and a gradual incrementalblending of the respective side angles of material repose to the rearangle of material repose.
 12. The process according to claim 11 whereinthe incremental blending of the side angles of material repose to thefront and rear angles of material repose includes dividing therespective rounded comers of the three-dimensional model into equalsegments, establishing a plane in each of these segments at a respectiveangle which allows an incremental change in the angles of materialrepose and extending the planes until they intersect the perimeter ofthe body.
 13. The process according to claim 10 further includingcomparing the three dimensional load model with the representation ofthe actual load information and adjusting the three dimensional loadmodel as necessary such that the three dimensional load modelsubstantially compares with the heaping characteristics of material tobe hauled at the anticipated point of use.
 14. The process according toclaim 1 wherein the heaping characteristics of material to be hauled atthe anticipated point of use further includes a density of the material.15. The process according to claim 1 wherein the heaping characteristicsof material to be hauled at the anticipated point of use accounts for amethod used for loading material into the vehicle body.
 16. The processaccording to claim 1 wherein developing the three dimensional model of aload to be carried in the body includes modeling corner voids of thehauled material into the three dimensional load model.
 17. The processaccording to claim 1 further including adjusting the set of designparameters to provide the lowest practical vertical location for thecenter of gravity of the three dimensional model of the hauled material.18. The process according to claim 1 further including adjusting the setof design parameters to allow material to be loaded into the body fromthe lowest practical vertical location.
 19. The process of claim 1wherein developing a three dimensional model of a load includesadjusting a heaping height of the three dimensional model to reflectheaping characteristics of material to be hauled at the anticipatedpoint of use for the vehicle.
 20. A process for making a body of avehicle for hauling material having a front wall, a pair of sidewallsand a rear edge, the process comprising: (a) developing athree-dimensional model of a load to be carried in the body on achassis, where the model incorporates angles of material repose in threedimensions for an actual load at an anticipated point of use andincludes representations of the conical shape of an actual load; (b)adjusting a set of design parameters of the body until the load modelcenter of gravity is located proximate a desired location for a loadcenter of gravity on a chassis of the vehicle and the volume of thethree-dimensional model is substantially similar to a desired volumetriccapacity of the vehicle; and (c) producing the body in accordance withthe adjusted set of design parameters.
 21. The process according toclaim 20 wherein the set of design parameters of the body includes aposition of the body floor and a position of the body sidewalls.
 22. Theprocess according to claim 21 wherein the position of the body floorincludes a length of the floor.
 23. The process according to claim 21wherein the position of the body sidewalls includes a height of thesidewalls.
 24. The process according to claim 23 wherein the position ofthe body sidewalls further includes a distance between the respectivesidewalls.
 25. The process according to claim 20 wherein the set ofdesign parameters of the body further includes a position of the bodyfront wall.
 26. The process according to claim 20 further includingadjusting the set of design parameters to provide the lowest practicalvertical location for the center of gravity of the three dimensionalmodel of the hauled material.
 27. The process according to claim 20further including adjusting the set of design parameters to allowmaterial to be loaded into the body from the lowest practical verticallocation.
 28. A process of making a body of a vehicle for haulingmaterial, the process comprising: (a) developing a three dimensionalmodel of a load to be carried in the body on a chassis, wherein themodel includes corner voids, a truncated peak, a volume and a center ofgravity and wherein the three-dimensional load model is developedthrough a gradual incremental blending of respective side angles ofmaterial repose to front and rear angles of material repose with theangles of material repose being those of particular material to behauled by the body; (b) adjusting a set of design parameters of the bodyuntil the load model center of gravity is located proximate a desiredlocation for a load center of gravity on a chassis of the vehicle andthe volume of the three dimensional model is substantially similar to adesired volumetric capacity; and (c) producing the body in accordancewith the set of adjusted design parameters.
 29. The process according toclaim 28 wherein the set of design parameters of the body includes aposition of the body floor and a position of the body sidewalls.
 30. Theprocess according to claim 29 wherein the position of the body floorincludes a length of the floor.
 31. The process according to claim 29wherein the position of the body sidewalls includes a height of thesidewalls.
 32. The process according to claim 31 wherein the position ofthe body sidewalls further includes a distance between the respectivesidewalls.
 33. The process according to claim 29 wherein the set ofdesign parameters of the body further includes a position of the bodyfront wall.
 34. The process according to claim 28 wherein theincremental blending of the side angles of material repose to the frontand rear angles of material repose includes dividing thethree-dimensional model into segments, establishing a plane in each ofthese segments at a respective angle which allows change in the anglesof material repose through the front, sides and rear of the threedimensional model and extending the planes until they intersect theperimeter of the body.
 35. A process of making a body of a vehicle forhauling material having a front wall, a pair of sidewalls and a rearedge, the process comprising: (a) collecting information describing athree-dimensional shape of a heaped load of material at an anticipatedpoint of use for the body; (b) developing from the collected informationa three-dimensional volumetric model of a load to be carried in the bodyon a chassis! (c) adjusting a set of design parameters of the body untilthe load model center of gravity is located proximate a desired locationfor a load center of gravity on a chassis of the vehicle and the volumeof the three-dimensional volumetric model is substantially similar to adesired volumetric capacity of the vehicle; and (d) producing the bodyin accordance with the adjusted set of design parameters.
 36. Theprocess according to claim 35 wherein the set of design parameters ofthe body includes a position of the body floor and a position of bodysidewalls.
 37. The process according to claim 35 wherein the informationcollected from the anticipated point of use includes angles of materialrepose of an actual load.
 38. The process according to claim 35 whereinthe information collected includes a density of the load material. 39.The process according to claim 35 wherein the collected informationaccounts for a method used for loading material into a vehicle body. 40.The process according to claim 35 wherein developing thethree-dimensional model of a load to be carried in the body includesdeveloping a generally rounded-off conical three-dimensional load model.41. The process according to claim 35 further including adjusting theset of design parameters to provide the lowest practical verticallocation for the center of gravity of the three dimensional model of thehauled material.
 42. The process according to claim 35 further includingadjusting the set of design parameters to allow material to be loadedinto the body from a lowest practical vertical location.
 43. A processof making a body of a vehicle for hauling material comprising: (a)developing a three dimensional model of a load to be carried in the bodyfrom information describing heaping characteristics of material to behauled at the vehicle's anticipated point of use; (b) adjusting a set ofdesign parameters of the body (1) until a volume of the threedimensional model is substantially similar to a desired volumetriccapacity and (2) to allow material to be loaded into the body from alowest practical vertical elevation over a floor of the body; and (c)producing the body in accordance with the adjusted set of designparameters.
 44. The process of claim 43 where the set of designparameters includes one or more of (1) a position of a floor of thebody, (2) a position of sidewalls of the body (3) a length of the floor,(4) a height of the sidewalls, (5) a distance between the sidewalls and(6) a position of a front wall of the body.
 45. The process of claim 43including adjusting the set of design parameters to locate a center ofgravity of material held in the body at approximately a lowest possibleposition for the center of gravity.
 46. A process of making a body of avehicle and for holding material of particular characteristics, theprocess comprising: (a) collecting data describing a three-dimensionalshape of an actual heap of the material, where the shape is affected bythe particular characteristics of the material and the data includesangles of repose for the heaped material; (b) determining a set ofdesign parameters for the body from the collected data; and (c)producing the body in accordance with the set of design parameters. 47.The process of claim 46 where the set of design parameters includes oneor more of (1) a position of a floor of the body, (2) a position ofsidewalls of the body, (3) a length of the floor, (4) a height of thesidewalls, (5) a distance between the sidewalls and (6) a position of afront wall of the body.
 48. The process of claim 46 including adjustingthe set of design parameters to locate a center of gravity of materialheld in the body at approximately a lowest possible position for thecenter of gravity.
 49. The process of claim 46 further includingadjusting the set of design parameters to allow material to be loadedinto the body from a lowest practical vertical elevation over a floor ofthe body.
 50. A process of making a body of a vehicle and for holdingmaterial, the process comprising: (a) modeling a three-dimensional loadof heaped material carried in the body, where the load has front, backand opposing side angles representing angles of repose for the material,the modeling including (1) truncating a peak of the heap and (2)blending each of the side angles to the front and rear angles; (b)selecting a set of design parameters for the body that locates thecenter of gravity for the modeled load proximate a desired location andprovides a volume of the modeled load that is substantially a desiredvolume; and (c) producing the body in accordance with the set of designparameters.
 51. The process of claim 50 where a shape of the modeledload approximates a cone truncated at its top and along sides and afront that are in contact with sides and front of the body beingmodeled.
 52. The process of claim 50 where the set of design parametersincludes one or more of (1) a position of a floor of the body, (2) aposition of sidewalls of the body (3) a length of the floor, (4) aheight of the sidewalls, (5) a distance between the sidewalls and (6) aposition of a front wall of the body.
 53. The process of claim 50including adjusting the set of design parameters to locate a center ofgravity of material held in the body at approximately a lowest possibleposition for the center of gravity.
 54. The process of claim 50 furtherincluding adjusting the set of design parameters to allow material to beloaded into the body from a lowest practical vertical elevation over afloor of the body.
 55. A process of making a body of a haulage vehiclecomprising: (a) collecting data describing angles of repose of heapedmaterial in three dimensions, where the data is from a workingenvironment for the haulage vehicle and the material is a particularmaterial whose characteristics affect the angles of repose; (b) modelinga body to hold a load of the material such that a center of gravity ofthe load determined from the collected data is proximate a desiredlocation; and (c) producing the body based on the modeling.
 56. Theprocess of claim 55 wherein the collected data includes informationregarding a shape of an actual load carried in an existing vehicle body.57. The process of claim 56 wherein the collected data includesinformation describing the heaped material's angles of repose fromfront, back and side walls of the body.
 58. The process of claim 55wherein the desired center of gravity is at a location approximating alowest possible position for the center of gravity.
 59. The process ofclaim 58 further including adjusting the height of sidewalls of the bodyto allow material to be loaded into the modeled body from a lowestpractical vertical elevation over a floor of the body.
 60. A process ofmaking a body of a haulage vehicle for hauling particular materialcomprising: (a) collecting data describing heaping characteristics ofthe particular material in three dimensions by observing heapingcharacteristics of either (1) the particular material to be hauled or(2) different material having substantially the same heapingcharacteristics of the particular material; (b) modeling in threedimensions a heaped load of the material to be carried in a body of thehaulage vehicle, where the modeled heaped load includes angles of reposederived from the collected data; and (c) producing the body to hold theheaped load of the material such that when the body is mounted on thehaulage vehicle and filled with an actual heaped load of the materialthe centroid of the actual heaped load is located proximate apredetermined location over a chassis of the haulage vehicle.
 61. Theprocess of claim 60 above wherein the modeling of the heaped load inthree dimensions includes modeling as a conical shape a section of theheaped load extending above the body, where the conical shapeincorporates the angles of repose derived from the collected data. 62.The process of claim 60 wherein the angles of repose result in anasymmetrical model of the heaped load.
 63. The process of claim 60wherein the angles of repose result in a symmetrical model of the heapedload.